Attempting Speedometer Repairs, Need some advice Options

[ericread]

For the past month, whenever I go above about 35 MPH, my speedometer begins to whine and the needle jumps around to a very high speed, far in excess of the speed I am traveling.

I first disassembled my speedometer.




There are basically two parts.

The part on the left connects the speedo with the cable, and causes a magnetic disc to spin. The part on the right has the speedometer dial and includes a metal ring of which the magnet spins inside. My understanding is that the magnet and the metal ring should never touch. The magnetic field from the magnet causes the ring to be advanced, which in turn causes the dial to advance.




Here we see the magnetic disc that spins from direct connection to the speedometer cable.



To the left of the speedometer dial, we can see the outside of the metal ring the magnet spins inside.



This is a picture of the metal ring.




Upon closer inspection, you can see some scoring on the upper right side of the inside ring. It appears that the spinning magnet is rubbing against the metal ring, which would explain the issues I have been experiencing. If I understand the theory of operation correctly, there should be no metal to metal contact here.





There are a two adjusting screws on the back of the magnet assembly. The flathead screw would seemingly adjust the magnet forward and back. Which direction should I go??? And the second adjustment is a very small screw with a retaining nut near the center of the moveable assembly. Will adjusting this screw move the magnet closer/farther from the metal ring? And what effect would this have on the speedometer reading?


Any thoughts?